Pump Pressure Fluctuation Amplitude Determination
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Solution Overview
Problem
Existing methods for determining the amplitude of pump-induced fluid pressure fluctuations in systems like SCR catalytic converters for reducing NOx emissions are impaired by interfering influences, leading to inaccurate amplitude values due to bouncing effects and regulation fluctuations, necessitating a precise and cost-effective solution.
Innovation Solution
A method that involves providing a pressure signal, determining its amplitude based on maximum and minimum values, and performing a plausibility check to ensure the signal represents a quasi-stationary state, using predetermined thresholds and pressure bands to validate the amplitude, thereby increasing the reliability of the determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If amplitude determination is performed using conventional methods in pump-regulated fluid systems, then the amplitude value can be obtained, but the determined value is inaccurate due to bouncing effects and regulation fluctuations
Solution Approach 1:
The patent applies preliminary action by performing a plausibility check on the pressure signal before determining the amplitude. The method checks whether the pressure signal satisfies predetermined plausibility criteria (such as signal stability, absence of bouncing effects, and regulation fluctuations within acceptable ranges) before proceeding with amplitude calculation. This preliminary validation ensures that only reliable pressure signals are used for amplitude determination, thereby improving both measurement precision and reliability.
2Ease of operation
If a simple amplitude determination method is used, then the procedure is easy to implement, but obvious irregularities and inaccuracies cannot be recognized immediately
Solution Approach 1:
The patent implements feedback by introducing a plausibility check that evaluates the pressure signal against predetermined criteria before amplitude determination. The system provides feedback on whether the signal is suitable for amplitude measurement by checking signal stability, detecting bouncing effects, and verifying regulation fluctuations. This feedback mechanism allows the system to automatically recognize and reject inaccurate measurements while maintaining a relatively simple overall procedure, thus improving reliability without significantly complicating the operation.
3Reliability
If pump movements are used to regulate fluid pressure, then the target pressure can be maintained, but pressure oscillations and fluctuations occur in the metering system
Solution Approach 1:
The patent applies the taking out principle by separating the amplitude determination process from the pressure regulation process. Specifically, it extracts and isolates the pressure signal analysis from the pump control loop by implementing a dedicated plausibility check that evaluates signal quality independently. This extraction allows the system to maintain pressure regulation functionality while simultaneously identifying and filtering out unstable signal portions caused by pump-induced oscillations, thereby addressing both the need for pressure maintenance and signal stability.
Data Source
AI summary
The invention relates to a method for determining an amplitude A of a pump-induced fluid pressure fluctuation of a fluid which is regulated to a desired fluid pressure psoll by means of a pump. In this case, the method comprises providing (S1) a pressure signal of the fluid, determining (S2) the amplitude A of the fluid pressure fluctuation on the basis of the pressure signal which has been provided, checking (S3) whether the pressure signal which has been provided satisfies a predetermined plausibility criterion, and outputting or rejecting (S4) the determined amplitude A on the basis of whether the pressure signal which has been provided satisfies the predetermined plausibility criterion. This advantageously provides a combined method in which, in addition to fundamentally determining the amplitude A of a fluid pressure fluctuation, a plausibility check is also carried out immediately in order to determine whether this fluid pressure fluctuation also actually corresponds to a representative value for the current system state. Furthermore, the invention also relates to a device which is designed to carry out the above-mentioned method and to a motor vehicle having a corresponding device.